The present invention relates to clamps for hoses and the like, and more particularly to improvements in clamps of the type wherein a length of springy material is convoluted into the form of a spiral which is placed around a portion of a hose to clamp the latter against a piece of pipe or the like.
It is already known to convolute a length of metallic wire into a spiral which forms more than one and a half convolutions and whose end portions extend outwardly to allow for the application of a force which tends to expand the clamp so as to allow for insertion or extraction of a piece of hose or the like. The inner diameter of the clamp is normally smaller than the outer diameter of the object to be clamped thereby so that the clamp must be expanded by increasing its inner diameter before it can be slipped onto a hose or the like. In accordance with a presently known proposal, the clamp consists of round wire and its cross-sectional area is constant from end to end, i.e., the outline of the wire is constant as well as the quantity of metallic material per unit length of the wire. This brings about the drawback that, when the radially outwardly bent end portions of the clamp are acted upon to expand the clamp, they tend to flex without causing any appreciable increase in the inner diameter of the clamp. Moreover, the end portions of such clamps, or the portions which are adjacent to the end portions, furnish a relatively small clamping force so that the hose is not gripped with a pronounced force and the force is not uniform all the way around the circumference of the hose. Reference may be had, for example, to German Offenlegungsschrift No. 30 26 582, to German Pat. No. 19 58 556 and to German Offenlegungsschrift No. 31 05 125.